Electronic timing device



Nov. 13, 1951 P. J. CADE 2,574,618

ELECTRONIC TIMING DEVICE Filed Feb. 14, 1947 2 SHEETS-SHEET 1 Ann Ann. 1 I I I I I I IIYIIY'" Nov. 13, 1951 P. J. CADE I 2,574,618

ELECTRONIC TIMING DEVICE Filed Feb. 14, 1947 2 SHEETS-SHEET 2 C/osed Open L I 39 7215 ape/73.9

PHILLIP J. CADE Patented Nov. 13, 1951 UNITED STATES PATENT OFFICE ELECTRONIC TIMING DEVICE Phillip J. (Jade, Sharon, Mass, assignor to Photoswitch, Incorporated, Cambridge, Mass, a corporation of Massachusetts Application February 14, 1947, Serial No. 728,501

9 Claims. 1

This invention relates to electronic control circuits in general, and particularly to time delay relays.

The electronic time delay relays generally known and used in industry have been found not to be universally and easily adaptable to numerous and varied timing problems. Dififerent industrial applications may require one or more of the following characteristics: a normally open or closed startingswitch; a latching relay in connection with the starting switch; non-repeat action; automatic repeat timing involving two timed intervals; non-beat characteristics; delayed-action timing; and impulse actuation. Previously, the electronic timers used in industry have been particularly designed for the characteristics required for the particular work to be performed by the timer.

For example, in photographic timing or in spot welding, it is required when a start switch is operated that the operating relay switch be closed and remain closed for a definite predetermined time interval at the end of which the operating relay switch will be open. Furthermore, it is use- 111 in such applications to employ a latching relay which will permit the release of the starting switch before the end of the time interval without interfering with the timing,

In testing electrical devices or apparatus, it is necessary that the apparatus being tested be rapidly connected to and disconnected from a power source for extended periods of time. Consequently, industrial timers are built which have an operating relay switch which is closed automatically for a series of predetermined time intervals, spaced by another series of predetermined time intervals.

Timers have been developed for stop motion alarms. In the operation of such timers, for example, the operating relay switch will remain closed so long as the motion being supervised remains Within a predetermined range of speed values. Such operation is effected, for example, by objects moving along a conveyor belt which momentarily closes a switch, and so long as the switch is operated successively at intervals less than a predetermined time interval the operating relay switch remains closed.

Other industrial applications of timers may include: a timer whose operating relay switch is normally closed and which opens at a predetermined time interval after a normally open start switch is closed; a timer whose operating relay closes upon the opening of a normally closed start switch with or without the use of a latching relay; a timer whose normally closed operating relay opens a predetermined time after a normally closed start switch is opened and kept open for a period greater than such predetermined time interval; or a timer whose operating relay closes upon the operation of one switch and opens a predetermined time after another switch is 0perated.

The timer of this invention was developed to provide one instrument the terminal connections of which could be varied as desired in order to secure operations equivalent to the various prior art timers enumerated above, as well as others not enumerated. Generally, the timing operations may be placed in three categories: automatic repeat timing where the operating relay is closed for successive timed intervals, each interval separated from the previous one by a timed period; interval timing where the operating relay changes position at the actuation of a starting switch and returns to its original position at the end of a predetermined time; and delayed action timing where the operating relay changes position at a predetermined time interval after the actuation of a starting switch. This timer is adapted to perform all of the above types of timing with normally open or normally closed control switches or a combination of normally open and closed control switches requiring either momentary actuation or actuation for the duration of the timed interval.

The main object of this invention is to provide a truly universal electronic timer adapted to be variously connected so as to perform various types of timed operations depending on the connections of the control terminals, such as, for example, automatic repeat timing, interval timing, and delayed action timing using normally closed or normally open control switches either momentarily actuated, or actuated for the duration of the timing interval.

It is another object of this invention to provide a simple, inexpensive, rugged and reliable electronic timing relay which uses a standard type of electron tube and is adapted for operation in various manners as set forth above.

Still another object of this invention is to provide a novel electronic timing relay employing a standard two-section electron tube in which the relay does not change position during the period required for warming up the heaters in the tube.

Still another object is to provide an electronic timing relay which, when used as a straight interval timer, may be used with either a normally open or a normall closed timing interval initiation switch.

In another aspect, it is one of the objects of this invention to provide a compact, simple, and rugged electronic timing device using a standard type of electron tube which is very flexible in its universal adaptability to timing operation requirements.

In still another aspect, this invention provides a timer which has a basic universally applicable circuit with specially arranged terminals which permits its application to diversified uses, avoiding the previous practice of designing a tin $9. every particular type of operation.

These and other objects, aspects and advantages will be apparent from the following description of a practical embodiment of this invention characterizing its nature by way of example. This description refers to a drawing in which:

Fig. 1 a circuit diagram of the electronic timer relay unit according to the invention;

Figs. 10. through 11 illustrate external circuit connections that may be used with the circuit of ie- Fig. 2 illustrates a simplified schematic circuit diagram of the circuit of Fig. 1 together with the external connections of Fig. lb;

Fig. 3 is a graphical illustration of the operation of the relay in the circuit of Fig. 2;

Fig. 4 illustrates a simplified schematic circuit diagram of the circuit of Fig. 1 together with the external connections of Fig. 111;

Fig. 5 is a graphical illustration of the operation of the relay in the circuit of Fig. 4;

Fig. 6 shows a simplified schematic circuit diagram of the circuit of Fig. 1 together with the external connections of Fig. 1f; and

Fig. '7 is a graphical illustration of the operation of the relay in the circuit of Fig. 6.

In the practical embodiment of the electronic timer relay illustrated by the circuit diagram of Fig. l, alternating current power is supplied to a transformer I having a primary 2 and a secondary 3. In Fig. l, the primary 2 has three terminals N, O, and P so that either one of two line voltages may be used. For example, the primary may be designed so that a line voltage of 230 volts may be connected to the two end terminals N and P or a line voltage of 115 volts may be applied to the center terminal 0 and either one of the two outside terminals N or P.

The secondary 3 of transformer I has two end terminals BI and 63 and an intermediate tap 62. In practical applications it has been found that a secondary giving 130 volts between the left hand end terminal El and the intermediate tap E32 and 145 volts between the right hand end terminal 53 and the intermediate tap 62 is suitable. A number of control terminals, denominated A, B, C, D, E, F, G, H, I, J, K, L, and M, respectively, are provided for purposes to be described herein. The left hand secondary winding terminal 6! is connected directly to a control terminal A, while the right hand secondary Winding terminal 63 is connected directly to control terminal M.

A two-section electron tube of suitable characteristics, such as, for example, a standard type GSN'l-GT tube, having an envelope 6, in the first section 65, an anode 9, a control grid 8 and a cathode 1, and in the second section 66, an anode 12, a control grid 1 I, and a cathode l0, together with cathode heaters (not shown), is connected as follows: the heaters (not shown) are supplied in any conventional fashion; the cathode 10 of the second section 66 is connected to the intermediate tap 62 on the secondary 3 of the transformer I; the cathode I of the first section 65 is connected directly to control terminal B and to one end of a potentiometer 35, the other end of which is connected to control terminal M; the movable tap 36 of the potentiometer 35 is connected directly to control terminal L; the cathode I of the first section 65 is connected also to one side of an energy storage condenser 4 across which is connected the dissipating resistor 5. The other side of the energy storage condenser 5 is connected to the control grid 8 of the first tube sec tion 65 directly to control terminal C, and to the anode I2 of the second tube section 68. The anode 9 of the first tube section 55 is connected in series with an electromagnet M to control terminal M. The electromagnet it is bridged by a by-pass condenser [3. The control grid ll of the second tube section 66 is connected to one side of the main energy storage condenser 24, the other side of which is connected directly to control terminal J and through a resistor 23 to control terminal K.

It will, of course, be apparent that two electron tubes of suitable characteristics may be used in place of the two-section electron tube.

An adjustable energy dissipation resistor unit 67 has tap switch 25 with its armature connected to control terminal J and four contact taps 21, 28, 29 and 30 connected each to one end of the dissipating resistors 3i, 32, 33 and 3G, respectively. The other ends of the resistors are joined together and connected to the control grid H of the second tube section 66.

The relay magnet I4 actuates a double-pole double-throw relay switch l5 comprising a singlepole double-throw auxiliary switch 53 and a single-pole double-throw operating switch 69 which have the two switch blades 15 and i? joined by insulating linkage [8. The switch blade 15 of the auxiliary switch 68 is connected to control terminal E and, when the electromagnet M is deenergized, is normally closed on contact 29, which is connected to control terminal F, and separated from contact I9 which is connected to control terminal D. The second switch blade I! in the operating switch 69 is connected to control terminal H and, when the electromagnet i4 is dcenergized, is normally closed on contact 22, which is connected to control terminal I, and is separated from contact 2| which is connected to control terminal G.

Fundamentally, the circuit of Fig. l is a twosection direct-coupled amplifier with a large timeconstant network in the grid circuit of the first amplifier section and a smaller time-constant network in both the output of the first amplifier section and the grid circuit of the second amplifier section. a

For basic operation, connections are made between control terminals J and L and between control terminals A and B by external connections as shown in Fig. 1b. These external connections are shown combined with the diagram of Fig. 1 in a simplified form in Fig. 2. A jumper 3i links control terminals J and L and a normally open push button start switch 39 is connected between control terminals A and B.

Alternating current is applied to the primary 2 of the power transformer l, either volts A. C. to terminals N and O, or 230 volts to terminals N and P, which develops alternating current potentials in the secondary 3. For example, the alternating potential between the secondary end terminals 6! and 63 may be 275 volts; between the left end terminal BI and the intermediate tap 62 there may be volts, and beintermediate tap 62.

tweenthe intermediate tap 62 and right hand terminal 63 there may be 145 volts.

Initially, push button switch 39 is open, that is, no power is furnished the first tube section 65 and consequently no current flow in the electro magnet l4. Power, however, is supplied to the second tube section 66 by the portion of the secondary 3 between the intermediate tap 62 and right hand end terminal 63, that is, to the anode I2 through the potentiometer resistor 35 and the grid capacitance 4 of first section 65 and its bridging resistor 5 and to the control grid H through a portion of resistor 35 and its movable tap 36, terminal L, and jumper 3?, terminal J and the energy storage capacitor 24 and one of its bridging resistors 3l-34, inclusive. The rectifying action of the second tube section 66 results in the building up of a large negative charge in the main capacitor 24, applied to the control grid ll so that the control grid l 1 becomes of approximately the same potential as its cathode [0.

The current through the anode l2 and grid capacitor 4 and the potentiometer 35 is not sufficient to build up any appreciable charge in the grid capacitor 4.

- Now, if the push button 39 is closed and held closed, the full alternating current power of the secondary 3 is put across the anode 9 and cathode of the first tube section 65 which conducts during the alternate half cycles when the anode 9 is at positive potential, thereby energizing the electromagnet 14 which promptly actuates the relay switch 15, closing switches 19 and 2!.

Before the closing of the push button switch 39, the main timing condenser 24 has become charged during the alternate half cycles when the secondary end terminal 63 is positive with respect to the intermediate tap 62 until the potential across it is substantially equal, but opposite in direction, to that across the portion of the secondary 3 between the intermediate tap 62 and the secondary end terminal 63 during said alternate half cycles. Consequently, terminal J is at approximately the same potential as the secondary end terminal 63 and the control electrode H is at approximately the same potential as the The closing of the push button switch 39 places the full potential of the transformer secondary 3 across the potentiometer 35 causing thereby a voltage drop to appear between the potentiometer tap 36 and the right hand secondary end terminal 63. Therefore, the control terminal J, depending on the position of the potentiometer tap 36, assumes a potential approximately that of the secondary intermediate tap 62 causing the main timing condenser to drive ly building up a potential across the grid condenser 4 until it becomes negatively charged on the side connected to the control grid 8 of the first tube section 65. When the negative charge on the control grid 8 becomes sufiiciently great with respect to the potential of cathode 7, the

--'current between anode 9 and cathode 1 of the 6 first tube section is reduced so that current no longer flows in the electromagnet [4, thereby permitting the relay switch 15 to open and ending the timed interval. The voltage necessary to terminate the timing interval is built up across the condenser 4 very quickly.

The voltage for cutting off the current through the first tube section 65 builds up very quickly in condenser 4 so that as a result the current through the electromagnet l4 quickly drops from a value which is sure to close the switch I5 to a value at which the switch 15 will be released, thereby securing sure, positive and accurate switching action.

The push button switch 39 may now be released, permitting the main timing condenser 24 to recharge, and returning the circuit to condition for the next actuation.

The condenser 4 discharges for a small but an appreciable time after the release of the push button switch 39 sufiicient to permit the recharging of the main timing condenser 24. Consequently, closing of the push button switch 39 during the discharge of condenser 4 will not operate the relay until the complete recharging of the main timing condenser 24, and, therefore, the timed intervals will be equal and precisely timed. The push button switch must be closed to operate the device of the invention only after the recharging of the main timing condenser 24.

If the push button switch 39 is permitted to open before the end of the timed interval, the application of power to anode 9 and cathode 1 of the first tube section 65 is terminated, the electromagnet I4 is thereby deenergized, and the circuit is returned to the condition where the main timing condenser 24 is charging. The operational sequence of the relay in this circuit is shown in graphical form in Fig. 3. The relay closes when the push button 39 is closed and remains closed until the end of the predetermined time interval unless the switch is opened before the end of the interval.

The external connections of Fig. la when ap plied to the devices of Fig. 1 set up an arrangement which operates in the same manner as explained above with relation to Figs. lb and 2, except that the relay is held operative during the timing interval. Fig. 1a shows in addition to the connection of Fig. 112, two jumpers 38 and 40 connecting the pairs of control terminals B and E, and A and D, respectively, thereby connecting across the starting switch 39 the normally open contacts of the auxiliary switch 68.

. When the starting switch 39 is closed and the electromagnet l4 energized, the auxiliary switch blade [6 closes on contact 19, thus completing a circuit from control terminal A through jumper 40, control terminal B, contact l9, blade l6, control terminal E and jumper 38, to control terminal B, thereby permitting the release of the starting switch 39 without interrupting the energization of the electromagnet 14 during the timing interval.

Fig. 1c shows external connections which, when applied to the circuit of Fig. 1, result in a form of operation that is similar to those forms described above. The normally open push button starting switch 42, although connected between control terminals D and E, is analogous to the starting switch 39 of Figs. 1a and lb since control terminal D is connected by jumper 4! to control terminal B, and control terminal E is connected by normally closed push button stop switch 43 to terminal A. This arrangement works exactly like that of Fig. 1a except that the stop switch 43 may be opened during the timing interval to break the external circuit from control terminal A to control terminal B, so that one can at will interrupt the timing operation as may be done by releasing push button 39 when using the external connections of Fig. 1b. In the arrangement of Fig. 10, however, it is not necessary to hold the start button 42 closed in order to secure a full timing interval.

The external connections shown in Figs. 1a, lb or in are particularly useful for photographic timing or for spot welding where it is necessary to have an accurately timed interval. For example,if the power circuit of a photographic enlarger is connected to terminals G and H with the connections of Fig. la, the momentary closing of starting switch 39 will turn on the power in the photographic enlarger for a timed interval which may be varied depending upon the amount of exposure required for the negative in the enlarger and the photographic paper being exposed. The use of the connections of Fig. 1b would require that the start button be held closed during the timing period. The use of the connections of Fig. 1c would permit the operator to stop the exposure by pushing the stop button 42.

The external connections of Fig. 1d may be used with the circuit of Fig. 1 when it is desired to have automatic repeat timing consisting of a series of timed intervals or operations of the relay switch I5, each timed interval being separated from the preceeding and succeeding intervals by shorter timed gaps. Fig. 4 shows in simplified form the external connections of Fig. id in connection with the devices of Fig. l, where this is accomplished by connecting a normally open starting switch 56 between control terminals A and B, by connecting together control terminals K and L through a jumper 64, and by connecting the normally closed portion of the auxiliary switch 68 across control terminals J and M through jumpers 45 and 46 connected between the two pairs of control terminals F and J and E and M, respectively. An additional capacitor 41 may be added between control terminals B and C to vary the timing of the gap between successive timed intervals. Until the starting switch 58 is closed there is no current through the first or second tube section 65 or 66, but the main timing condenser 24 becomes charged by grid current flowing from grid H to cathode it of the second section 56. At the closing of the starting switch 56, current flows in the first tube section 65, starting the timed operation, and causing the timing condenser 24 to block the second tube section 56 by opening of the normally closed portion |62G of the auxiliary switch 68. The timed interval continues until the timing condenser 24 dissipates its energy, thus permitting current in the second tube section 66 to flow, charging the grid condenser 4 (and auxiliary condenser 4?, if any) and thereby ending the timed interval by cutting ofi the first tube section 55. Thereupon the auxiliary switch 68 is released and reclosed, recharging the timing condenser 24 and cutting on" the second tube section E5. The grid condenser 4 (and the auxiliary condenser 4?, if any) discharges until the first tube section 65 becomes conductive, thereby timing the gap between consecutive timed intervals and initiating the next timed interval. The operation will now keep on repeating until the starting switch is opened.

Fig. 5 is a graphical representation of the relay g operation of the circuit of Fig. 4 or that of Fig. 1 with the connections of Fig. 1d. The use of the timer with these connections for life testing is readily apparent. The power for the apparatus to be tested is connected through terminals G and H, for example, so that the power to the apparatus is turned on for a set time interval and then turned off for another timed interval and the operations therein repeated for an extended period until the start switch 56 is opened.

Fig. lc shows another method in which the device of the invention illustrated in Fig. 1 may be connected and used for time delay operation of a normally closed relay: where it is desired to have a normally closed relay switch open at a predetermined time interval after the closing of a starting switch. Two pairs of control terminals, A and B, and K and M, are connected by jumpers 48 and 55, respectively. A normally open push button starting switch 49 is connected between terminals J and L. Application of power to primary winding 2 of transformer 1 results in the application of power to the first tube section 65, and after the cathodes l0 and I are heated causes energizationof the electromagnet l4 and charging of the main timing condenser 24 and consequent closing of the relay switch 15. Closing of the starting switch 49 initiates the dis charge of the timing condenser 24 and the running of the time interval at the end of which the second tube section 66 becomes conductive, causing, in the manner previously explained, the cutting off of the first tube section 65, the deenergization of the electromagnet l4, and the consequent opening of the relay switch [5. If starting switch 49 is opened during the timed interval, the timing is stopped and the timing condenser 24 is recharged and the relay switch l5 remains closed. When the starting switch 49 is opened after the completion of the timing interval the timing condenser 24 is recharged and the second tube section is cut off, the first tube section 65 becomes conductive, relay magnet 14 is energized, and the relay switch [5 is closed. All is now in readiness for another operation.

Fig. 1; and (in simplified form) Fig. 6 show a mode of utilizing the device of the invention to control an operation initiated by the momentary opening of a starting switch during which operation the control relay i5 is closed. Paired terminals A and B, K and L, and J and F are connected by jumpers 48, 44, and 45, respectively, and a normally closed push button starting switch 5| is connected between terminals A and E. Fig. 7 shows graphically the relay operation. Initially, the timing condenser 24 is charged negative through the circuit 63-35-5l-E-|6-20- F-45-J-24-l l-l0-62. The second tube section 66 is conducting, grid condenser 4 is charged, the first tube section 65 is non-conductive, the electromagnet I4 is deenergized, and auxiliary switch blade i6 is closed on contact 20. Opening starting switch 5! makes control grid II more negative than the cathode ID by cutting on the second tube section 66 and consequently permitting the first section 65 to become conductive, energizing the electromagnet l4, and breaking the contact between relay switch blade l6 and contact 20 to maintain the charging circuit 63-35'-5l-E-l6-2 ll- F-45-J-24-l l-l062 open even though the starting switch 5| is immediately reclosed. The timing condenser 24 discharges until the end of the present time interval, when the second tube section 66 becomes conductive again, building up a a cut-off potential in grid condenser 4 so that the first tube section 65 is out off, deenergizing the electromagnet l4 and permitting relay switch blade 16 to close on contact 20 to reestablish the aforementioned charging circuit.

Fig. lg shows a modification of the immediately aforementioned mode of utilization having in addition to the elements of Fig. 1f a normally open stop switch 52 connected between terminals B and F. Closing the stop switch 52 during the timing interval serves to reinitiate the circuit to charge the timing condenser 24, and reduces the negative potential on the control grid ll of the second section 66, permitting the second tube section to conduct current and cut off the first tube section 65, deenergizing the electromagnet 14 before the end of the time interval.

Fig. 1h shows another mode of utilization which operates similarly to those of Figs. 1 and 19/, having paired terminals A and B, and K and L, connected together by jumpers 48 and 44, re-

spectively, and having a normally closed push button starting switch 53 connected between terminals B and J. Operation is similar to the circuit of Figs. 1 and 1g except that the starting switch 53, analogously to the starting switch of Figs. 1 and lg, must remain open during the preset time interval, since the electromagnet l4 does not open any auxiliary relay switch. Also, the starting switch 53, if it is closed during the time interval, acts as a stop switch analogously to the stop switch 52 of Fig. 1g.

Fig. 12' shows the paired terminals A and B, and K and L, connected by jumpers 48 and 44, respectively, and a normally closed starting switch 54 connected between terminals J and M. Initially, upon the application of power to primary 2 of transformer I, after the cathodes I and i5 have heated up, the timing condenser 24 charges through circuit B3-M-54-J-24-l I-lfl-BZ, and the first tube section becomes conductive, thereby energizing electromagnet l4 and closing the relay switch l5 on contacts [9 and 2|. Opening the starting switch 54 causes the control grid I! to become negative with respect to cathode Ill. The first tube section 55 remains conductive until the discharge of timing condenser 24 causes the second tube section 65 to become conductive, charging the condenser 4 and causing control grid 8 to become negative with respect to cathode l and cutting off the first tube section 65. Thereupon, the electromagnet I4 is deenergized and relay switch 15 changes positions. If starting switch 54 is closed during the time interval, the discharge of the timing condenser 24 is stopped and the circuit returns to the initial conditions, the relay switch l5 remaining unchanged in position.

Fig. 17', like Fig, 1c, shows a jumper 55 connecting the pair of control terminals K and M and a normally open push button switch 55 connected between control terminals J and L but having the connections of Fig. la. between control terminals A and B instead of those of Fig. 1e; that is, a normally open push button switch 59 connected between control terminals A and B and jumpers 45 and 38 between pairs of control terminals A and D, and B and E, respectively. Closing of push button switch 39 closes and latches the relay, setting up the device for the closing of push button switch 49 to initiate the timing interval at the end of which the relay opens. To secure another timed interval, it is necessary again to close the push button switch 35. Push button switch 49 must be maintained closed during the timed 10 interval; otherwise, the relay will remain closed and it will be necessary to close the switch again to restart the timed interval.

Fig. 17c shows a jumper 44 connecting terminals K and L, the normally open push button start switch 3% connecting terminals A and B as in Fig. lb, and a normally closed push button stop switch 54 like the starting switch of Fig. 12 connected between terminals J and M. The arrangement of Fig. 17c operates in essentially the same manner as the arrangement of Fig. 12', except that the relay switch 15 is not closed until starting switch 39 is closed, and the opening of switch 35 when the relay switch l5 is closed will open the relay switch l5. Opening switch 54 and maintaining it open will initiate the timing operation at the end of which the relay will close.

Fig. ll shows terminal pairs A and D, B and E, and K and L connected by the jumpers 40, 38 and 44, respectively, the normally open push button starting switch 39 connected between terminals A and B, and a normally open push button impulse switch 55 connected between terminals J and M.

Initially, the timing condenser charges through the circuits G335L-44-K23-24-l l-IO- 62. Closing the starting switch 39 energizes the electro-magnet i4, closing the holding relay switch 15-!!! during the timing interval. The discharge of timing condenser 24 proceeds until the second tube section 56 conducts current, thereby charging condenser 4 and cuttin off the first tube section 65, and deenergizing the electromagnet l4. If during the timed interval impulse switch 55 is closed, the timing condenser 24 is recharged through circuit 63-M-55-J-24 45-62 and the electromagnet remains energized. When the impulse switch 55 is released, the timed interval is reinitiated by making the control grid H of the second tube section 66 negative with respect to the cathode Ill.

The above-described operation of the circuit of Fig. 1 with the connections of Fig. ll are particularly useful in stop motion control industrial applications. For example, each object traveling on a conveyor belt may be made to actuate the impulse switch 55 as the object passes a given point. The conveyor is started by closing the start button 39, thereby closing the relay switch, the conveyor power supply being connected through terminals G and H. So long as the objects travel along the belt properly spaced at such a rate that the impulse switch 55 is actuated within the timing interval each time an object passes the given point, the relay switch will remain closed keeping the conveyor 'connected to the power but if the conveyor should stop or if there should be no further objects on the conveyor or if the spacing deviates from a suitable range, then the impulse switch 55 will' not be actuated within the timed interval and the relay will open, thereby deenergizing the conveyor.

Many oth r uses and applications of the timer of this invention will be readily apparent.

Since certain changes may be made in the above-described article and dififerent embodiments of the invention could be made without departing from the scope thereof, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative only and not in a limiting sense.

What is claimed is:

1. A time delay electron relay device comprising: a first electron discharge device having at least a first anode, a first cathode, and a, first control electrode; a second electron discharge device having at least a second anode, a second cathode, and a second control electrode; a first control terminal; a first energy storage and dissipation means connected between said first control electrode and said first control terminal; a second energy storage and dissipation means connected between said second cathode and said second control electrode; a connection from said first anode to said second control electrode; a source of alternating current connected between said second cathode and said second anode and having an intermediate tap connected to said first cathode; a second and a third control terminal disposed between said source and said second cathode and adapted unless interconnected to interrupt the supply of energy from said source; voltage divider means having an adjustable tap connected to a fourth control terminal, said divider means being connected across said second cathode and said second anode; and operator means responsive to the fiow of current in said second discharge device; and means for interconnecting a plurality of said control terminals to determine the operating characteristics of the device.

2. A time delay electronic relay device comprising; a first electron discharge device having at least a first anode, a first cathode, and a first control electrode; a second electron discharge device having at least a second anode, a second cathode, and a second control electrode; a first control terminal; a first energy storage and dissipation means connected between said first control electrode and said first control terminal; second energy storage and dissipation means connected between said second cathode and said second control electrode; a connection from said first anode to said second control electrode; a source of alternating current connected between said second cathode and said second anode and having an intermediate tap connected to said first cathode; a second and a third control terminal between said source and said second cathode and adapted unless interconnected to interrupt the supply of energy from said source; voltage divider means connected across said second cathode and second anode having an adjustable tap connected to a fourth control terminal; operator means responsive to the flow of current in said second discharge device; switching means having at least a fifth and a sixth control terminal; means responsive to said operator means for interconnecting said fifth and sixth terminals; adapted for interconnection in response to said operator means; and means for interconnecting a plurality of said first four terminals to determine the operating characteristics of the device.

3. A time delay electronic relay device comprising: a first electron discharge device having at least a first anode, a first cathode, and a first control electrode; a second electron discharge device having at least a second anode, a second cathode, and a second control electrode; a first control terminal; first energy storage and dissipation means connected between said first control electrode and said first control terminal; second energy storage and dissipation means connected between said second cathode and said second control electrode; said first anode being connected to said second control electrode; a source of alternating current connected between said second cathode and said second anode and having an intermediate tap connected to said first cathode; a second and a third control terminal disposed between said source and said second cathode and adapted unless interconnected to interrupt the supply of energy from said source; voltage divider means connected across said second cathode and second anode and having an adjustable tap connected to a fourth control terminal; operator means responsive to the fiow of current in said second discharge device; and switching means having at least a fifth, a sixth, and seventh control terminal, said fifth terminal being connected to said sixthv or said seventh terminal in response to said operator means; and means for interconnecting a plurality of said control terminals to determine the operating characteristics of the device,

4. A time delay electron relay device comprising: a first electron discharge device having at least a first anode, a first cathode, and a first control electrode; a second electron discharge device having at least a second anode, a second cathode, and a second control electrode; control switch means; a source of alternating current connected between said second anode and said second cathode through said control switch means, and said source having an intermediate tap connected to said first cathode; a shunting resistor-capacitor time delay network; voltage divider means connected across said source and said control switch and having an adjustable tap connected to said first control electrode through said shunting resistor-capacitor time delay network; a second capacitor bridged by a dissipating resistor connected from said second cathode to said second control electrode, a connection from said second control electrode to said first anode; and operator means responsive to the flow of current in said second device.

5. A time delay electronic relay device comprising: a first electron discharge device having at least a first anode, a first cathode, and a first control electrode; a second electron discharge device having at least a second anode, a second cathode, and a second control electrode; operator means responsive to the flow of current through said second device; an alternating current source connected to said second anode and to said second cathode through a switch means responsive to said operator means, and said source having an intermediate tap connected to said first cathode; a time delay network; voltage divider means connected between said second cathode and said second anode and having an adjustable tap connected through said time delay network to said first control electrode; and energy storage and dissipation means connected from said second cathode to said second control electrode and said first anode.

6. A time delay electronic relay device comprising: a first electron discharge device having a first anode, a first cathode, and a first control electrode; a second electron discharge device having a second anode, a second cathode, and a second control electrode; current responsive operator means; a power transformer having a secondary winding with one end connected to said second cathode and the other end connected to said second anode through said current responsive operator means, and said winding having an intermediate tap connected to said first cathode; voltage divider means connected across said secondary and having an adjustable tap; a first time delay network connected between said first control electrode and said adjustable tap; energy storage and dissipation means connected between said second cathode and said second control electrode; a connection between said second control electrode and said first anode; and switch means for controlling the connection of said first time delay network to said second cathode.

7. A time delay electronic relay device comprising: a first electron discharge device having a first anode, a first cathode, and a first control electrode; a second electron discharge device having a second anode, a second cathode, and a second control electrode; current responsive operator means; a power transformer having a secondary winding with one end connected to said second cathode and the other end connected to said second anode through said current responsive operator means, and said winding having an intermediate tap connected to said first cathode; voltage divider means connected across said secondary winding and having an adjustable tap; a first time delay network connected between said first control electrode'and said adjustable tap; energy storage and dissipation means connected between said second cathode and said second control electrode; a connection between said second control electrode and said first anode; and switch means for controlling the connection of said first time delay network to said other end of said secondary winding.

8. A time delay electronic relay device comprising: a first electron discharge device having a first anode, a first cathode, and a first control electrode; a second electron discharge device having a second anode, a second cathode. and a second control electrode; a power transformer having a secondary winding with first and second end terminals and an intermediate tap; current responsive operator means connected between said second anode and said second end terminal; voltage divider means connected between said second end terminal and said second cathode and having an adjustable tap; a first time delay network connected between said first control electrode and said second end terminal; energy storaze and dissipation means connected between said second control electrode and said second cathode; a connection between said second control electrodeland said first anode; a first normally open switch means connecting said first end terminal and said second cathode; and latching relay means actuated by said operator bridging said second switch means.

9. A time delay electronic relay device comprising: a first electron discharge device having a first anode, a first cathode, and -a first control electrode; a second electron discharge device having a second anode, a second cathode, and a second control electrode; a power transformer having a; secondary winding with a first and a second end terminal and an intermediate tap; current responsive operator means connected between said 'second anode and said second end terminal; a voltage divider means connected between said second end terminal and said second cathode and having an adjustable tap; a time delay network connected between said first control electrode and said adjustable tap; energy storage and dissipation means connected between said second control electrode and said second cathode; a connection between said second control electrode and firstanode; a first switching means connecting said first network and said second end terminal; andja second switching means connecting said first end terminal and said second cathode.

- PHILLIP J. CADE.

REFERENCES CITED The following references are of record in the 

